Added network sim function.

Fixes #1.
Sort gene names in parameters.
Added matrix <-> adjacencyList functions.

Added functions to convert adjacency lists to/from adjacency matrices along with a few tests.
Created tri2mat to convert triangular to full matrix.

Closes #4.
Added the edgeCutoff function with tests.

Closes #2
Added PPI network data, updating documentation.
Added examples, corrected tests.

Added requirement of GeneNet, WGCNA, parmigene, and space. This can be reevaluated in the future, but it was nice to use those packages during the examples knowing that they'd be available. Also, it would likely be more convenient for the user to have them all installed automatically. The only downside would be the increase in wait-time to run the package after opening all of the other dependencies.
Cleaned up doc, bumped version.
Added changelog and updated README.
Update CHANGELOG.md

Corrected spacing.
Merged with Master